I could seine you could seine she could seine we could seine you could seine they could seine
V-ing form
I could be seining you could be seining she could be seining we could be seining you could be seining they could be seining
Perfect
I could have seined you could have seined she could have seined we could have seined you could have seined they could have seined
V-ing perfect
I could have been seining you could have been seining she could have been seining we could have been seining you could have been seining they could have been seining
Negation
Simple form
I could not seine you could not seine she could not seine we could not seine you could not seine they could not seine
V-ing form
I could not be seining you could not be seining she could not be seining we could not be seining you could not be seining they could not be seining
Perfect
I could not have seined you could not have seined she could not have seined we could not have seined you could not have seined they could not have seined
V-ing perfect
I could not have been seining you could not have been seining she could not have been seining we could not have been seining you could not have been seining they could not have been seining
Interrogative form
Simple form
could I seine? could you seine? could she seine? could we seine? could you seine? could they seine?
V-ing form
could I be seining? could you be seining? could she be seining? could we be seining? could you be seining? could they be seining?
Perfect
could I have seined? could you have seined? could she have seined? could we have seined? could you have seined? could they have seined?
V-ing perfect
could I have been seining? could you have been seining? could she have been seining? could we have been seining? could you have been seining? could they have been seining?
Interro-negative form
Simple form
could I not seine? could you not seine? could she not seine? could we not seine? could you not seine? could they not seine?
V-ing form
could I not be seining? could you not be seining? could she not be seining? could we not be seining? could you not be seining? could they not be seining?
Perfect
could I not have seined? could you not have seined? could she not have seined? could we not have seined? could you not have seined? could they not have seined?
V-ing perfect
could I not have been seining? could you not have been seining? could she not have been seining? could we not have been seining? could you not have been seining? could they not have been seining?